By Jim Moore, Entomologist
Summertime is the season for tending all the vegetables and flowers in my gardens. I focus on those kind of flowers that attract flower-loving bugs; and I do get swarms of them: bees, wasps, butterflies, beetles, and other kinds of bugs. And then there are the predators: spiders, robber flies, damselflies, and dragonflies.
This year the top predator was a dragonfly called the Eight-Spotted Skimmer, species Libellula forensis.
Several of these dragonflies established their small territories by resting upon the tops of the rather tall stakes that I use to tie up the branches of my cherry tomato plants. They often dart out and catch the smaller flying insects, and then quickly return to their prized perches to consume their prey.
The Eight-Spotted Skimmer is so named for the eight black spots on it’s wings. All males and only some females display eight white spots on their wings, spots appear only on mature adults. They have a wing span of about three inches.
The aquatic nymphs of Eight-Spotted Skimmers live in ponds and lakes with muddy bottoms, where they feed on other small aquatic insects such as the larvae of mosquitos, midges, and mayflies. They are well camouflaged to match the muddy bottom of their water domains. The fully grown nymphs usually crawl up onto vegetation or exposed rock where they emerge as adult Dragonflies leaving behind strange looking nymphal skins.
A very similar dragonfly is the Twelve-Spotted Skimmer, species Libellula pulchella, and is differentiated by having an additional large dark spot on each of the four wing tips. The Libellula Skimmer Dragonflies species in North America are so named because they often fly close to the surface waters of ponds and lakes. Skimmers are also sometimes called ‘Perchers’ because of their habit of perching on tips and sides of bare twigs, branches, and reeds. It is said that a single adult dragonfly can eat over one hundred mosquitos in one day.
Hmmm, I should probably place a few more perching stakes here and there around the yard!